feat: add native skill tool with permission system (#5930)

Co-authored-by: Dax Raad <d@ironbay.co>

packages/opencode/src/session/compaction.ts

@@ -40,6 +40,8 @@ export namespace SessionCompaction {
   export const PRUNE_MINIMUM = 20_000
   export const PRUNE_PROTECT = 40_000
 
+  const PRUNE_PROTECTED_TOOLS = ["skill"]
+
   // goes backwards through parts until there are 40_000 tokens worth of tool
   // calls. then erases output of previous tool calls. idea is to throw away old
   // tool calls that are no longer relevant.
@@ -61,6 +63,8 @@ export namespace SessionCompaction {
         const part = msg.parts[partIndex]
         if (part.type === "tool")
           if (part.state.status === "completed") {
+            if (PRUNE_PROTECTED_TOOLS.includes(part.tool)) continue
+
             if (part.state.time.compacted) break loop
             const estimate = Token.estimate(part.state.output)
             total += estimate